1. Field of the Invention
The present invention relates to a transmitter and receiver integrated optical sub-assembly and an optical module.
2. Description of the Related Art
The wavelength division multiplexing (WDM) is known as a technology with which the transmission capacity per optical fiber is increased. With the WDM, optical signals having different wavelengths are multiplexed so as to increase the transmission capacity.
As related-art optical sub-assemblies supporting the WDM, a transmitter optical sub-assembly (TOSA) and a receiver optical sub-assembly (ROSA) are known. The TOSA includes a plurality of light emitting elements that emit beams of light at different light emission wavelengths and combines the beams emitted from the light emitting elements into a beam so as to output the combined beam. The ROSA splits an input optical signal (an optical signal obtained by multiplexing optical signals of different wavelengths) into optical signals of the different wavelengths which are each received by a corresponding one of a plurality of light receiving elements (see, for example, Japanese Unexamined Patent Application Publication Nos. 2013-145356 and 2014-137475). U.S. Pat. No. 7,933,521 is also an example of related art.
The related-art optical modules can perform transmission and reception using the TOSA and the ROSA housed in a common casing. Typically, the TOSA and the ROSA are included in respective separate optical sub-assemblies, and accordingly, include their respective housings.